Threatened status of neglected and underutilised Jatropha (Euphorbiaceae) species endemic to Mexico

Jatropha curcas is the best known species from the genus, an oilseed crop used for biodiesel production. It deserves attention as more species show similar oil content, phytochemical properties, or as a genetic resource in J. curcas breeding programs. The closest species to J. curcas show restricted distributions and are included in the IUCN Red List. In this study, the geographical distribution and conservation status was determined for 24 species in of the subgenus Curcas endemic to the Neotropic, except J. curcas, 20 are endemic to Mexico. Nine hundred and ninety-four herbarium specimens were used to assess their status by applying the IUCN Red List Categories and Criteria. The analysis shows that 11 species are threatened: 2 are critically endangered, 6 endangered and 3 vulnerable. Additionally, 5 species were assessed as nearly threatened, 4 as least concern and 2 as data deficient. Except for J. contrerasii and J. websteri, the threatened species have a narrow altitude range (< 500 m). With a growing emphasis on the exploitation of neglected and under-utilised species such as Jatropha, it is important to establish systematic collections for the assessment of threat status and to develop management strategies for their conservation.